Factors Affecting Rate of Reaction

Influencing the rate of a reaction

Not all reactions occur at the same rate. The rusting of a bicycle is a slow reaction, while the combustion of magnesium is fast. The speed of a reaction is called the reaction rate. This indicates how much of a substance disappears or is formed per second There are five factors which will influence the rate of a reaction:

1. When magnesium and zinc are each reacting with hydrochloric acid, a solution of hydrogen chloride in water, magnesium will react much faster than zinc. The type of reactants therefore influences the rate of the reaction.

2. Magnesium powder reacts much faster with hydrochloric acid than a magnesium ribbon. The magnesium powder is more finely divided than the magnesium ribbon; it has a much larger surface area. Evidently, the reaction rate increases when a substance is more finely divided.

3. If you put two equal pieces of magnesium in two hydrochloric acid solutions of different concentrations, the hydrochloric acid with the higher concentration will react faster with the magnesium. The greater the concentration, the faster the reaction will proceed.

4. The reaction between magnesium and hydrochloric acid will proceed faster in warm hydrochloric acid than in hydrochloric acid at room temperature. A higher temperature results in a faster reaction.

5. You can influence the reaction rate with a catalyst. A catalyst is an auxiliary substance that ensures that a reaction will proceed faster. There is no catalyst for the reaction between magnesium and hydrochloric acid. Therefore, this way of increasing the rate of a reaction does not work for every reaction.